Sunrise 6:01 AM   Sunset 7:54 PM Moonrise 12:08 AM   Moonset 8:56 AM

  Print   HELP   Reset   Save   Recall

FXUS63 KILX 300322 AFDILX

Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1022 PM CDT Mon Apr 29 2024

KEY MESSAGES

- Patchy fog will develop across much of central and southeast Illinois tonight...with a 30-50% chance of visibilities dropping below 1/4 mile in spots along/south of a Danville to Taylorville line.

- Above normal temperatures will prevail for the remainder of the week.

- The next significant chance for rain will arrive Thursday into Friday, followed by slightly cooler conditions by next weekend.

UPDATE
Issued at 811 PM CDT Mon Apr 29 2024

Slow moving cold front was located between I-55 and I-57 at 8 pm.
Back edge of the rain has moved into the extreme southeast CWA near Lawrenceville and will completely exit the area over the next 1-2 hours. Behind the front, dew points fell into the upper 40s and lower 50s. With the front washing out over the area, MSLP gradient relaxes overnight and the dry advection will lose its southeast push, leaving areas near and south of I-70 with dewpoint depressions approaching zero late tonight. This combined with wet ground from today's rainfall should lead to the formation of fog, some of which could become dense at times. The presence of high clouds streaming northeast from a southern stream shortwave lowers confidence in dense fog coverage. Latest high resolution guidance does show areas of dense fog south of I-70 primarily between 1-7 am. Will monitor trends over the next several hours, and a dense fog advisory may eventually be needed. Aside from this, weather will be quiet for the remainder of the area overnight with lows ranging from the upper 40s/lower 50s over central IL, to the upper 50s in SE IL.

25

SHORT TERM
(Tonight through Tuesday)
Issued at 302 PM CDT Mon Apr 29 2024

19z/2pm surface analysis shows a weak cold front pushing slowly eastward through the Illinois River Valley. Low clouds persist east of the front, with persistent showers impacting locations along/southeast of a Paris to Effingham line. Showers will continue across the far E/SE KILX CWA through early evening before gradually pushing further eastward into Indiana. The cold front will eventually exit the CWA as well, but this will not occur until late evening. While the upstream airmass behind the boundary is considerably drier with current dewpoints only in the 40s across Iowa/far western Illinois, this airmass will only gradually trickle eastward after FROPA. As a result, there will be quite a bit of lingering boundary layer moisture. Given clearing skies and light winds, patchy fog looks to be a good bet...especially across the E/SE where the drier air will be slowest to arrive.
HRRR/RAP/GFSLAMP all suggest the potential for locally dense fog in a few spots across this area. In addition, the 12z Apr 29 HRRR indicates a 30-50% chance of visibilities dropping below 1/4 mile along/south of a Danville to Taylorville line. Am not confident enough to issue a Dense Fog Advisory at this time, but have included areas of fog across the E/SE accordingly. After any early morning fog dissipates, Tuesday looks to be a mostly sunny and pleasant spring day with high temperatures topping out in the middle to upper 70s.

Barnes

LONG TERM
(Wednesday through Next Monday)
Issued at 302 PM CDT Mon Apr 29 2024

A short-wave trough is progged to eject northeastward out of the Rockies on Tuesday, then track into the Upper Midwest by Wednesday.
While the strongest lift associated with this feature will remain well northwest of Illinois, it will drag a weak cold front into north-central Illinois by early Wednesday. Scattered showers and perhaps a thunderstorm will precede the front Tuesday night with any showers dissipating before daybreak Wednesday. Despite the lingering weak boundary in the area, short-wave ridging aloft in the wake of the system will ensure a warm/dry day on Wednesday with high temperatures topping out in the upper 70s/lower 80s.

A more significant short-wave will cross the Rockies into the Plains by Thursday...and this system will bring the next significant chance of rain to central Illinois by the end of the week. 12z models continue to be too fast with the eastward progression of this amplifying system, so rain chances Wednesday night/Thursday morning will likely be removed as models come into better focus. The main window for the strongest forcing/deepest moisture continues to look like Thursday afternoon through Friday morning when GFS precipitable water values increase to 1.50-1.75.
Have therefore carried likely to categorical PoPs during that timeframe.

Once the late week system passes, slightly cooler/drier weather can be expected Friday night into Saturday before another short- wave trough approaches by Sunday.

Barnes

AVIATION
(For the 06z TAFs through 06z Tuesday Night)
Issued at 1022 PM CDT Mon Apr 29 2024

VFR TAFs this cycle. Light northwest winds will become variable/calm at times tonight, then increase from the south around 10 kt by mid morning. A decaying thunderstorm complex is forecast to approach KPIA from the northwest toward 06z Wed, and included a PROB30 to account for this.

25

ILX WATCHES/WARNINGS/ADVISORIES
Dense Fog Advisory until 9 AM CDT Tuesday for ILZ062-063-066>068- 071>073.

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Central Illinois, IL,